<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let score = +prompt('输入成绩:')
        if(score>=90){
            document.write('优秀')
        }
        else if(score>=70){
            document.write('良好')
        }
        else if(score>=60){
            document.write('及格')
        }
        else{
            document.write('不及格')
        }
        //三元运算符
        let i = +prompt('输一个数')
        let c = +prompt('输第二个数:')
        x=i<c ? i : c
        document.write(x)
        
        let x = +prompt('输入一个数:')
        y=x<10 ? '0'+x:x
        document.write(y)
        //switch语句
        let a =+prompt('输入一数:')
        let b =+prompt('输入二数:')
        let fu = prompt('符号')
        switch (fu) {
            case '+':
              alert(a+b)  
                break;
            case '-':
              alert(a-b)  
                break;
            case '*':
              alert(a*b)  
                break;
            case '/':
              alert(a/b)  
                break;
            default:
                alert('other')
                break;
        }
    </script>
</body>
</html>